Sarepta Halts Development of New Duchenne Drug

Sarepta Therapeutics has decided to cease the development of vesleteplirsen, an experimental exon 51-skipping therapy designed for patients with Duchenne muscular dystrophy who have specific mutations. This decision also extends to all other programs utilizing the same peptide, as confirmed by Louise Rodino-Klapac, the head of Research and Development, during a call with analysts. This includes the approaches for other exons like 45 and 53, as communicated by a spokesperson via email.

Several factors have influenced this decision. The information available to date, the risk-benefit profile of the program, feedback from the U.S. Food and Drug Administration (FDA), and the changing therapeutic landscape for Duchenne muscular dystrophy all played a role, as stated in Sarepta's third-quarter earnings report. Additionally, there have been cases of persistent hypomagnesemia, or abnormally low magnesium levels, even after patients stopped the treatment, Rodino-Klapac noted. The FDA also indicated that the data available did not support the possibility of an accelerated approval pathway for the drug.

Vesleteplirsen, also known by its code SRP-5051, was considered a next-generation iteration of Exondys 51, Sarepta's initial exon-skipping drug, which had received accelerated approval in 2016. In a Phase 2 study, results reported in January showed that among 20 patients who received a high dose of vesleteplirsen, there was an average dystrophin expression of 5.17%. For the 20 patients who received a lower dose, the average dystrophin expression was 2.81%.

In other news, Sarepta reported significant revenue from its Duchenne gene therapy, Elevidys, reaching $181 million, which exceeded Wall Street's expectations. Additionally, there were $9.5 million in royalties from Roche, which is in charge of commercializing Elevidys outside the United States. This comes after the FDA granted Elevidys a controversial expanded label in June, making the therapy available to a broader group of Duchenne muscular dystrophy patients aged 4 and older.

The discontinuation of vesleteplirsen and related programs marks a significant shift in Sarepta's strategy as they navigate the complexities of developing effective treatments for Duchenne muscular dystrophy. The company remains committed to advancing other promising therapies in its pipeline and optimizing its resources to bring meaningful treatments to patients in need.